Method and system for inter-fabric routing

ABSTRACT

A Fibre Channel Switch element and method for Inter-Fabric routing is provided. The switch element includes a switch port whose worldwide port number is used in a zone set to enable Inter-Fabric frame routing without using Inter-Fabric frame headers. The method includes querying a Name Server to determine world wide port numbers of devices; storing query results in an Inter-Fabric Name Server module; extracting world wide port numbers for each switch port; registering Proxy Devices with the Name Server, wherein the Proxy Devices interface with the switch ports as if it was they were actual devices to route Inter-Fabric frames; and establishing Fabric Address Translator entries so that source identification values and destination identification values are mapped to route Inter-Fabric frames without using Inter-Fabric frame headers.

BACKGROUND

1. Field of the Invention

The present invention relates to Fibre Channel network systems, and moreparticularly, to Inter-Fabric routing.

2. Background of the Invention

Fibre Channel is a set of American National Standard Institute (ANSI)standards, which provide a serial transmission protocol for storage andnetwork protocols such as HIPPI, SCSI, IP, ATM and others. Fibre Channelprovides an input/output interface to meet the requirements of bothchannel and network users.

Fibre Channel supports three different topologies: point-to-point,arbitrated loop and Fibre Channel Fabric. The point-to-point topologyattaches two devices directly. The arbitrated loop topology attachesdevices in a loop. The Fibre Channel Fabric topology attaches hostsystems directly to a Fabric, which are then connected to multipledevices. The Fibre Channel Fabric topology allows several media types tobe interconnected.

Fibre Channel Fabric devices include a node port or “N_Port” thatmanages Fabric connections. The N_port establishes a connection to aFabric element (e.g., a switch) having a Fabric port or “F_port”.

A Fibre Channel switch is a multi-port device where each port manages apoint-to-point connection between itself and its attached system. Eachport can be attached to a server, peripheral, I/O subsystem, bridge,hub, router, or even another switch. A switch receives messages from oneport and routes it to another port.

Most Fibre Channel SANs are currently used as “SAN Islands”. The termisland as used herein means an isolated fully contained SAN. The use ofSAN islands has been common because switch suppliers have forced limitson SAN size and Information Technology managers have been reluctant tobuild larger SANs due to concerns about fault containment.

Inter-Fabric routing is an emerging concept in which SAN islands operateindependently but can access devices among themselves using Inter-SAN(or Inter Fabric) routers. New header types are being proposed tofacilitate Inter-Fabric routing. One disadvantage of this approach isthat switch devices have to accommodate new header types, new Fabricrouting protocols and extensions.

Therefore, there is a need for a method and system that can accommodateInter-Fabric routing under current Fibre Channel protocol without havingto rely on new headers, extensions and protocol changes.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a Fibre Channel Switch elementis provided. The switch element includes a switch port whose world wideport number is used in a zone set to enable Inter-Fabric frame routingwithout using Inter-Fabric frame headers.

In another aspect of the present invention, a Fibre Channel network isprovided. The network includes at least two Fabrics coupled to a hostsystem and a target device; and a Fibre Channel switch elementcomprising at least a switch port whose world wide port number is usedin a zone set to enable Inter-Fabric frame routing without usingInter-Fabric frame headers.

In yet another aspect of the present invention, a method for routingInter-Fabric frames using a Fibre Channel switch element with pluralports is provided. The method includes querying a Name Server todetermine world wide port numbers of devices; storing query results inan Inter-Fabric Name Server module; extracting world wide port numbersfor each switch port; registering Proxy Devices with the Name Server,wherein the Proxy Devices interface with the switch ports as if theywere actual devices, to route Inter-Fabric frames; and establishingFabric Address Translator entries so that source identification valuesand destination identification values are mapped to route Inter-Fabricframes without using Inter-Fabric frame headers.

In yet another aspect of the present invention, a method for routingInter-Fabric frames is provided. The method includes receiving a framefrom a Native Device with a proxy D_ID for a Proxy device; deliveringthe frame to a port that manages the Proxy Device; replacing the proxyD_ID with a D_ID of an actual target device; and replacing native S_IDwith a proxy S_ID; and delivering the frame to a destination Fabric.

This brief summary has been provided so that the nature of the inventionmay be understood quickly. A more complete understanding of theinvention can be obtained by reference to the following detaileddescription of the preferred embodiments thereof concerning the attacheddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features and other features of the present invention willnow be described with reference to the drawings of a preferredembodiment. In the drawings, the same components have the same referencenumerals. The illustrated embodiment is intended to illustrate, but notto limit the invention. The drawings include the following Figures:

FIG. 1A shows an example of a network system used according to oneaspect of the present invention;

FIG. 1B shows an example of a Fibre Channel switch element, according toone aspect of the present invention;

FIG. 1C shows a block diagram of a 20-channel switch chassis, accordingto one aspect of the present invention;

FIG. 1D shows a block diagram of a Fibre Channel switch element withsixteen GL_Ports and four 10G ports, according to one aspect of thepresent invention;

FIGS. 1E-1/1E-2 shows a top-level block diagram of a switch element usedaccording to one aspect of the present invention;

FIG. 1F shows the Inter-Fabric structure used, according to one aspectof the present invention;

FIG. 2 shows a block of a switch element, according to one aspect of thepresent invention; and

FIG. 3 shows a process flow diagram for Inter-Fabric routing, accordingto one aspect of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS DEFINITIONS

The following definitions are provided for convenience as they aretypically (but not exclusively) used in the Fibre Channel environment,implementing the various adaptive aspects of the present invention.

“CRC” (cyclic redundancy code): A 4 byte value used for checking dataintegrity of a Fibre Channel frame.

“D_ID”: A 24-bit Fibre Channel header field that contains thedestination address for a frame.

“E_Port”: An expansion port that is used to connect Fibre Channel Switchelements in a Fabric.

“Fabric”: The structure or organization of a group of switches, targetand host devices (NL_Port, N_ports etc.).

“Fabric Tag”: An identifier assigned to each Fabric and it's value isset to the port number of the SF_Port that has a native connection tothe Fabric.

“FAT”: Fabric Address Translator that monitors incoming frames, comparesD_ID and S_ID values, and when a match is found, replaces the D_ID andS_ID values with those contained within FAT and then recalculates theCRC for integrity check.

“F_Port”: A port to which non-loop N_Ports are attached to a Fabric anddoes not include FL_ports.

“Fibre Channel ANSI Standard” (“FC-FS-2”): The standard (incorporatedherein by reference in its entirety) describes the physical interface,transmission and signaling protocol of a high performance serial linkfor support of other high level protocols associated with IPI, SCSI, IP,ATM and others.

“Inter Fabric Header”: The Inter Fabric Routing Extended Header(IFR_Header) is used for routing Fibre Channel frames from one Fabric toanother. It provides the Fabric identifier of the destination Fabric,the Fabric identifier of the source Fabric and information to determinehop count.

“Inter-Fabric Name Server” (INS) : This provides an Inter-Fabric superset Name Server database for all attached Fabrics and includesconnectivity state information for Inter-Fabric bridged devices.

“Native Device”: This is a logical or physical device that is a part ofa SAN and can be shared among multiple Fabrics.

Native Fabric: This is the Fabric where the Native Device resides.

“N_Port”: A direct Fabric attached port, for example, a disk drive or aHBA.

“NL_Port”: A L_Port that can perform the function of a N_Port.

“Proxy Device”: This is a logical device that represents a NativeDevice. The Proxy Device resides in a Proxy Fabric.

“Proxy Fabric”: A Fabric that can access/utilize a Native Device withouthaving the Native Device actually reside in the Fabric.

“S_ID”: A 24-bit, Fibre Channel Source identifier that identifies thesource of a frame.

“Switch”: A Fabric element conforming to the Fibre Channel Switchstandards.

SF_Port: A Synthetic Fabric Port that emulates N_port behavior withrespect to an external switch and performs Inter-Fabric bridging portfunctionality within a Synthetic Fabric Switch.

Synthetic Fabric Switch: A switch, according to one aspect of thepresent invention that facilitates Inter-Fabric routing.

In one aspect of the present invention, a Fabric Switch is provided thatcan handle Inter-Fabric routing. The switch operates as a bridge betweendifferent Fabrics and uses an Inter-Fabric zone set with an Inter-FabricName Server.

To facilitate an understanding of the preferred embodiment, the generalarchitecture and operation of a Fibre channel System and a Fibre Channelswitch element will be described. The specific architecture andoperation of the preferred embodiment will then be described withreference to the general architecture.

Fibre Channel System:

FIG. 1A is a block diagram of a Fibre Channel system 100 implementingthe methods and systems in accordance with the adaptive aspects of thepresent invention. System 100 includes plural devices that areinterconnected. Each device includes one or more ports, classified asnode ports (N_Ports), Fabric ports (F_Ports), and expansion ports(E_Ports). Node ports may be located in a node device, e.g. server 103,disk array 105 and storage device 104. Fabric ports are located inFabric devices such as switch 101 and 102. Arbitrated loop 106 may beoperationally coupled to switch 101 using arbitrated loop ports(FL_Ports).

The devices of FIG. 1A are operationally coupled via “links” or “paths”.A path may be established between two N_ports, e.g. between server 103and storage 104. A packet-switched path may be established usingmultiple links, e.g. an N_PORT in server 103 may establish a path withdisk array 105 through switch 102.

Fibre Channel Switch Element:

FIG. 1B is a block diagram of a 20-port ASIC Fabric element according toone aspect of the present invention. FIG. 1B provides the generalarchitecture of a 20-channel switch chassis using the 20-port Fabricelement. Fabric element includes ASIC 20 with non-blocking Fibre Channelclass 2 (connectionless, acknowledged) service and class 3(connectionless, unacknowledged) service between any ports. It isnoteworthy that ASIC 20 may also be designed for class 1(connection-oriented) service, within the scope and operation of thepresent invention as described herein.

The Fabric element of the present invention is presently implemented asa single CMOS ASIC, and for this reason the term “Fabric element” andASIC are used interchangeably to refer to the preferred embodiments inthis specification. Although FIG. 1B shows 20 ports, the presentinvention is not limited to any particular number of ports.

ASIC 20 has 20 ports numbered in FIG. 1B as GL0 through GL19. Theseports are generic to common Fibre Channel port types, for example,F_Port, FL_Port and E_PORT. In other words, depending upon what it isattached to, each GL port can function as any type of port. Also, the GLport may function as a special port useful in Fabric element linking, asdescribed below.

For illustration purposes only, all GL ports are drawn on the same sideof ASIC 20 in FIG. 1B. However, the ports may be located on both sidesof ASIC 20 as shown in other figures. This does not imply any differencein port or ASIC design. Actual physical layout of the ports will dependon the physical layout of the ASIC.

Each port GL0-GL19 is comprised of transmit and receive connections toswitch crossbar 50. Within each port, one connection is through receivebuffer 52, which functions to receive and temporarily hold a frameduring a routing operation. The other connection is through a transmitbuffer 54.

Switch crossbar 50 includes a number of switch crossbars for handlingspecific types of data and data flow control information. Forillustration purposes only, switch crossbar 50 is shown as a singlecrossbar. Switch crossbar 50 is a connectionless crossbar (packetswitch) of known conventional design, sized to connect 21×21 paths. Thisis to accommodate 20 GL ports plus a port for connection to a Fabriccontroller, which may be external to ASIC 20.

In the preferred embodiments of switch chassis described herein, theFabric controller is a firmware-programmed microprocessor, also referredto as the input/output processor (“IOP”). As seen in FIG. 1B,bi-directional connection to IOP 66 is routed through port 67, whichconnects internally to a control bus 60. Transmit buffer 56, receivebuffer 58, control register 62 and Status register 64 connect to bus 60.Transmit buffer 56 and receive buffer 58 connect the internalconnectionless switch crossbar 50 to IOP 66 so that it can source orsink frames.

Control register 62 receives and holds control information from IOP 66,so that IOP 66 can change characteristics or operating configuration ofASIC 20 by placing certain control words in register 62. IOP 66 can readstatus of ASIC 20 by monitoring various codes that are placed in statusregister 64 by monitoring circuits (not shown).

FIG. 1C shows a 20-channel switch chassis S2 using ASIC 20 and IOP 66.IOP 66 in FIG. 1C is shown as a part of a switch chassis utilizing oneor more of ASIC 20. S2 will also include other elements, for example, apower supply (not shown). The 20 GL_Ports correspond to channels C0-C19.Each GL_Port has a serial/deserializer (SERDES) designated as S0-S19.Ideally, the SERDES functions are implemented on ASIC 20 for efficiency,but may alternatively be external to each GL_Port. The SERDES convertsparallel data into a serial data stream for transmission and convertsreceived serial data into parallel data. The 8 bit to 10 bit encodingenables the SERDES to generate a clock signal from the received datastream.

Each GL_Port may have an optical-electric converter, designated asOE0-OE19 connected with its SERDES through serial lines, for providingfibre optic input/output connections, as is well known in the highperformance switch design. The converters connect to switch channelsC0-C19. It is noteworthy that the ports can connect through copper pathsor other means instead of optical-electric converters.

FIG. 1D shows a block diagram of ASIC 20 with sixteen GL ports and four10G (Gigabyte) port control modules designated as XG0-XG3 for four 10Gports designated as XGP0-XGP3. ASIC 20 include a control port 62A thatis coupled to IOP 66 through a PCI connection 66A.

FIGS. 1E-1/1E-2 (jointly referred to as FIG. 1E) show yet another blockdiagram of ASIC 20 with sixteen GL and four XG port control modules.Each GL port control module has a Receive port (RPORT) 69 (similar to58, FIG. 1B) with a receive buffer (RBUF) 69A (similar to 58, FIG. 1B)and a transmit port (T PORT) 70 with a transmit buffer (TBUF) 70A(similar to 56, FIG. 1B). GL and XG port control modules are coupled tophysical media devices (“PMD”) 76 and 75 respectively.

Control port module 62A includes control buffers 62B and 62D fortransmit and receive sides, respectively. Module 62A also includes a PCIinterface module 62C that allows interface with IOP 66 via a PCI bus66A.

XG_Port (for example 74B) includes RPORT 72 with RBUF 71 similar toRPORT 69 and RBUF 69A and a TBUF 74B and TPORT 74A similar to TBUF 70Aand TPORT 70. Protocol module 73 interfaces with SERDES to handleprotocol based functionality.

Incoming frames are received by RPORT 69 via SERDES 68 and thentransmitted using TPORT 70. Buffers 69A and 70A are used to stage framesin the receive and the transmit path.

FIG. 1F shows an example of Inter-Fabric connections used, according toone aspect of the present invention. Eight Fabric switch are shown(numbered 1 through 8) to illustrate Inter-Fabric routing. Switch # 1 iscoupled to Switch # 2, while Switch # 3 is coupled to Switch # 1 and 2.Fabric 1 includes Switch #1,2, and 3.

Fabric 2 includes Switch 4, 5 and 6. Fabric 3 includes Switch 5 andSwitch 7, while Fabric 4 includes Switch 6 and Switch 8. It isnoteworthy that the present invention is not limited to any particularnumber of Fabrics or switches.

FIG. 2 shows a block diagram of a Synthetic Fabric Switch (may also bereferred to as Switch) 200 with a plurality of SF_Ports 203 (shown asSF_Port1, SF_PORT2 . . . SF_Port3). Switch 200 supports Inter-Fabricrouting without using Inter-Fabric headers. It achieves this by provingProxy Devices and address translation. Bridging between Fabrics isenabled when there is a pair of Inter-Fabric SF_Port World Wide PortNumber (SF_port WWPN) entries in at least one Inter-Fabric Zone Set witha common zone name. The zoning information is maintained in a databaseshown as Inter-Fabric Zone Set (database) 201. It is noteworthy thatdatabase 201 can be stored on switch 200 memory or accessible to switch200. The zone sets and the way they are used are described below in moredetail.

Each SF_Port 203 has access to a Fabric Address Translation module(“FAT”) 204 (shown as FAT1, FAT2 and FAT3 for each SF_Port1, SF_Port2and SF_Port3, respectively). FAT 204 performs address translation thatis used to move frames between different ports.

Each SF_Port is attached to a Fabric Switch, shown as Fabric SwitchDomain 205, 206 and 207. Each Fabric Switch can be coupled to varioustargets and host systems (via host bus adapters (HBAs)). For example,Fabric Switch 205 is coupled to HBA 208 (shown as HBA 1) and to Target(which includes storage devices and/or storage sub-systems) 209 (shownas Target 1). Fabric Switch 206 is coupled to HBA 210 and Target 211(shown as Target 2), while Fabric Switch 207 is coupled to HBA 212 andTarget 213 (shown as Target 3).

Each SF_Port gets a unique identifier (“ID”) when it logs in. Forexample, SF_PORT 1 has the following identifier: 20.8.0, where 20denotes the Domain ID for Fabric Switch 205, 8 denotes the Area ID forFabric Switch 205 and 0 is the Port ID for SF_Port1. Similarly, SF_Port2 has a unique ID value shown as 21.9.0, where 21 is the Domain ID, 9 isthe Area ID and 0 is the Port ID; while SF_Port 3 has an identifiershown as 22.10.0, where 22 is the Domain ID, 10 is the Area ID and 0 isthe Port ID.

Fibre Channel Standard FC-SW-2, incorporated herein by reference in itsentirety, defines Fibre Channel switch addressing. Typically, a 24-bitidentifier is used to uniquely identify a switch. The 24 bit addressincludes a 8-bit Domain Identification (“Domain_ID.”) number; 8-bit AreaIdentifier (Area_ID) and 8-bit Port Identifier (Port_ID), as stated inFC-SW_2 Section 4.8, incorporated herein by reference in its entirety.

Domain_ID identifies a domain of one or more switches that have the sameDomain_ID for all N_Ports and NL_Ports (an N Port that can perform anArbitrated Loop function). A domain in the Fibre Channel environment asdefined in FC-SW-2, incorporated herein by reference in its entirety, isthe highest or most significant hierarchical level in a three-leveladdressing scheme. If there is more than one switch in a Fabric, theneach switch within the Fabric shall be assigned a Domain ID and it isdirectly connected via an inter-switch link (“ISL”) to at least anotherswitch in the Fabric.

Fibre Channel Generic Services (FC-GS-3) specification describes insection 5.0 various Fibre Channel services that are provided by FibreChannel switches including using a “Name Server” to discover FibreChannel devices coupled to a Fabric. FIG. 2 shows an example of a NameServer 202A. It is noteworthy that Name Server 202A can be locatedanywhere in the network.

A Name Server provides a way for N_Ports and NL_Ports to register anddiscover Fibre Channel attributes. Request for Name server commands arecarried over a Common Transport protocol, also defined by FC-GS-3. TheName Server information is distributed among Fabric elements and is madeavailable to N_Ports and NL_Ports after the ports have logged in.

Various commands are used by the Name Server protocol, as defined byFC-GS-3, for registration, de-registration and queries. Fiber ChannelSwitched Fabric (FC-SW-2) specification describes how a Fabricconsisting of multiple switches implements a distributed Name Server.

After an SF_Port logs in, it queries the Name Server to determine theunique World Wide Numbers (WWNs) of the devices that are logged intotheir Native Fabric. In the FIG. 2 example, HBA 208 and Target 209 arepart of Native Fabric Domain 20, while HBA 210 and Target 211 are partof Domain 21 and HBA 212 and Target 213 are part of Domain 22. The queryresults are then stored in Inter-Fabric Name Server (INS) 202.

INS 202 includes the standard Name Server information, but also includesProxy Device and Proxy Fabric information, as described below. INS 202notifies each SF_Port of the devices to which they can have access.

Each SF_Port performs a Virtual N_Port login for devices that are notcoupled to a Native Fabric (or for Proxy Devices). For example, as shownin FIG. 2, the following assignments are made: T2 is the proxy targetfor Target 2 (211) and is made available via SF_Port1. T2 has anidentifier of 20.8.1, where 20 is the Domain, 8 is the area value forFabric Switch 205 and 1 is the virtual N_Port identifier for T2.

H3 is the Proxy Device for HBA 3 (212) and is available via SF_Port1 viaFAT1 (204). The proxy identification values for H3 are 20 (Domain), 8(Area) and 2 (port identifier). Similarly, T3 is the Proxy Device forTarget 3 (213) with identifier values of 21 (domain), 9 (area) and 3(port identifier). H1 is the Proxy Device for HBA 1 (208) withidentifier values of 21 (Domain), 9 (Area) and 4 (port address). T1 isthe Proxy Device for Target 1 (209) and H2 is the Proxy Device for HBA 2(210).

Each SF_Port registers each Proxy Device with the Name Server usingentries from INS 202. For example, SF_Port 1 registers proxy devices T2and H3 with the virtual N_Port identification values. FAT 204 entriesand steering paths are established upon PLOGI. The WWNs of initiatorsand targets are verified based on Inter-Fabric Zone set 201 and INS 202entries. Routing of frames use certain mappings/translations that aredescribed below with respect to the process flow diagram of FIG. 3.

FIG. 3 shows a process flow diagram for using Switch 200 in Inter-Fabricrouting. Switch 200 allows devices (i.e. hosts and storage systems) tocommunicate with each other even though they have different NativeFabrics. This is achieved by using Proxy Devices and Virtual N_Portidentifiers.

Turning in detail to FIG. 3, in step S300, after Switch 200 is poweredup, each SF_Port performs a PLOGI. PLOGI is a standard log in procedurethat is performed under the established Fibre Channel standards.

In step S302, each SF_Port queries the Name Server to determine theunique identifiers (for example, WWNS) for each device. In step S304,the query results are stored in INS 202.

In step S306, each SF_Port extracts the unique identifiers ofdevices/hosts to which it has access. This information is used foraddress translation. The identifiers in this case include informationregarding Native Fabric devices and the Proxy Devices.

In step S308, each SF_Port registers the Proxy devices with the NameServer. For example, SF_Port 1 in FIG. 2 will register the proxy devicesT2 and H3, SF_Port 2 registers T3 and H1, while SF_Port 3 registers T1and H2.

In step S310, Inter-Fabric Address Translator entries are populated.Thereafter, each unique identifier for the initiators/targets isverified as members of Inter-Fabric Zone set 201. The user defines theInter-Fabric Zone set.

In step S312, translation mapping values for initiator SF_Ports andtarget Fabric SF_Port are set. Thereafter, in step S314, auto-routingbetween plural devices is enabled.

An example of auto-routing with respect to FIG. 2 is now provided. Thefollowing translations will occur if HBA 1 (208) attached to FabricSwitch 205 wants to communicate with Target 2 (211) attached to FabricSwitch 206. The D_ID for T2 is converted from the Virtual Port ID valueto the actual Target 2 value. The S_ID for a frame is converted from theactual S_ID of HBA 1 (208) to the proxy S_ID of H1, where H1 is theProxy device for SF_Port 2. The inverse translation occurs when Target 2responds to HBA 1.

FIG. 4 shows a top-level process flow diagram for routing frames betweenFabrics using the switch configuration described above with respect toFIG. 3. The process begins in step S400, when a Native Device sends aframe with a proxy D_ID. For example, Native Device, HBA 208 sends theproxy D_ID for Proxy Device T2.

In step S402, the Native Fabric switch delivers the frame to the SF_Portthat manages the Proxy Device. In the foregoing example, Fabric Switch205 forwards the frame to SF_Port 1 (shown as 203 in FIG. 2).

In step S404, FAT 204 modifies the frame header. In particular, theactual Native D_ID (for Target 2 (211) replaces Proxy D_ID for T2. TheS_ID is also modified from the Native Fabric to the Proxy S_ID for thedestination Fabric. In this example, the S_ID of HBA 1 (208) is changedto the S_ID of Proxy Device H1.

In step S406, the frame is delivered via crossbar 50 to destinationFabric. In this example, the frame is delivered from Fabric 205 toFabric 206 via SF_Port 1 and SF_Port 2. Thereafter, in step S408, thedestination Fabric delivers the frame to the destination. In theforegoing example, Fabric Switch 206 delivers the frame to Target 2.

In one aspect of the present invention, a Fibre Channel switch elementcan enable Inter-Fabric auto-routing of frames by using SF_Ports. Thisdoes not require Inter-Fabric headers and extensions.

Although the present invention has been described with reference tospecific embodiments, these embodiments are illustrative only and notlimiting. Many other applications and embodiments of the presentinvention will be apparent in light of this disclosure and the followingclaims.

1. A Fibre Channel Switch element, comprising: a switch port whose worldwide port number is used in a zone set to enable Inter-Fabric framerouting without using Inter-Fabric frame headers.
 2. The Fibre ChannelSwitch element of claim 1, further comprising: a Fabric AddressTranslator module that modifies source identification values anddestination identification values for Inter-Fabric frame routing.
 3. TheFibre Channel Switch element of claim 1, wherein a virtual N_Portidentification value is used to create a proxy device, wherein the proxydevice interfaces with a switch port as if it was the actual device toroute Inter-Fabric frames.
 4. The Fibre Channel Switch element of claim1, wherein the switch port after log in queries a Name Server todetermine world wide port numbers of all attached devices and storesquery results in an Inter-Fabric Name Server.
 5. The Fibre ChannelSwitch element of claim 4, wherein the switch port registers all ProxyDevices with the Name Server.
 6. The Fibre Channel Switch element ofclaim 5, wherein translation mappings are set for initiator switch portand target switch ports.
 7. A method for routing Inter-Fabric framesusing a Fibre Channel switch element with plural ports, comprising:querying a Name Server to determine world wide port numbers of devices;storing query results in an Inter-Fabric Name Server module; extractingworld wide port numbers for each switch port; registering Proxy Deviceswith the Name Server, wherein the Proxy Devices interface with theswitch ports as if it was they were actual devices to route Inter-Fabricframes; and establishing Fabric Address Translator entries so thatsource identification values and destination identification values aremapped to route Inter-Fabric frames without using Inter-Fabric frameheaders.
 8. The method of claim 7, wherein the Inter-Fabric Name Serveris a database.
 9. The method of claim 7, wherein the Fabric AddressTranslators are available to each switch port.
 10. The method of claim9, wherein the Fabric Address Translators perform address translation toroute Inter-Fabric frames.
 11. A Fibre Channel network comprising: atleast two Fabric coupled to a host system and a target device; and aFibre Channel switch element with at least a switch port whose worldwide port number is used in a zone set to enable Inter-Fabric framerouting without using Inter-Fabric frame headers.
 12. The network ofclaim 11, wherein the Fibre Channel Switch element further comprising aFabric Address Translator module that modifies source identificationvalues and destination identification values for Inter-Fabric framerouting.
 13. The network of claim 1, wherein a virtual N_Portidentification value is used to create a proxy device, wherein the proxydevice interfaces with a switch port as if it was the actual device toroute Inter-Fabric frames.
 14. The network of claim 1, wherein theswitch port after log in, queries a Name Server to determine world wideport numbers of all attached devices and stores query results in anInter-Fabric Name Server.
 15. The network of claim 4, wherein the switchport registers all Proxy Devices with the Name Server.
 16. The networkof claim 15, wherein translation mappings are set for initiator switchport and target switch ports.
 17. A method for routing Inter-Fabricframes, comprising: receiving a frame from a Native Device with a proxyD_ID for a Proxy device; delivering the frame to a port that manages theProxy Device; replacing the proxy D_ID with a D_ID of an actual targetdevice; and replacing native S_ID with a proxy S_ID; and delivering theframe to a destination Fabric.
 18. The method of claim 17, wherein aFabric Address Translator replaces the proxy D_ID.
 19. The method ofclaim 18, wherein the Fabric Address Translator replaces the nativeS_ID.
 20. The method of claim 17, wherein a virtual N_Portidentification value is used to create a proxy device, wherein the proxydevice interfaces with the switch port as if it was the actual device toroute Inter-Fabric frames.
 21. The method of claim 17, wherein theswitch port after log in queries a Name Server to determine world wideport numbers of all attached devices and stores query results in anInter-Fabric Name Server.
 22. The method of claim 21, wherein the switchport registers all Proxy Devices with the Name Server.